1. Field of the Invention
The present invention relates to an oil pump unit for an internal combustion engine.
2. Background of the Invention
There is a case where an internal combustion engine is provided with an oil pump that is disposed in an engine case constituting an oil storage portion so as to improve the oil suction efficiency of the pump (see, for example, Japanese Patent Laid-open No. Sho 63-76952).
A lubricating device of the internal combustion engine disclosed in Japanese Patent Laid-open No. Sho 63-76952 is of a dry sump type and is such that an oil pump unit including respective united pump cases of a scavenging pump and a feed pump is disposed in a clutch chamber whose bottom portion serves as an oil storage portion.
The oil pump unit is configured differently from an engine case constituting the clutch chamber and is installed in the clutch chamber in such a manner that the pump case itself is provided with an oil intake port adapted to suck the oil collecting in the oil storage portion by the drive of the pump, and with an oil discharge port and the like.
Thus, the oil pump unit configured differently from the engine case is increased in the number of the component parts so that the pump case tends to be configured in a complicated manner to increase in size as well as in weight.